Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Quem ganhou o torneio de simples masculino em 1999?
 ###Tabelas: CREATE TABLE previous_winners (previous_winners_id AUTO_INCREMENT PRIMARY KEY, Year INT, Men's singles VARCHAR, Women's singles VARCHAR, Men's doubles VARCHAR, Women's doubles VARCHAR, Mixed doubles VARCHAR) CREATE TABLE list_of_ministers (list_of_ministers_id AUTO_INCREMENT PRIMARY KEY, Minister VARCHAR, Party VARCHAR, Governments VARCHAR, Term start VARCHAR, Term end VARCHAR) CREATE TABLE 1950s (1950s_id AUTO_INCREMENT PRIMARY KEY, Debut year INT, Player VARCHAR, Games INT, Goals INT, Years at club VARCHAR) CREATE TABLE season_6_2009–11 (season_6_2009–11_id AUTO_INCREMENT PRIMARY KEY, Series # INT, Season # INT, Title VARCHAR, Directed by VARCHAR, Written by VARCHAR, Original air date VARCHAR, Production code INT) CREATE TABLE top_ten_scorers (top_ten_scorers_id AUTO_INCREMENT PRIMARY KEY, Name VARCHAR, Hometown VARCHAR, Games VARCHAR, Goals VARCHAR, Assists VARCHAR, Points VARCHAR, Pen. Min. VARCHAR)  
SELECT Men's singles FROM previous_winners WHERE Year = 1999